Wafer-level methods of fabricating semiconductor device packages and related packages

ABSTRACT

Methods of fabricating semiconductor device packages may involve forming trenches in a first wafer. A dielectric material may be placed over a first active surface. Electrically conductive elements may be operatively connected to bond pads of a second wafer with the dielectric material interposed between the first wafer and the second wafer. Force may be applied to the first wafer and the second wafer while exposing the first wafer and the second wafer to an elevated temperature. Portions of the dielectric material may flow into the trenches. The elevated temperature may be reduced to at least partially solidify the dielectric material. A thickness of the first wafer may be reduced to reveal the portions of the dielectric material in the trenches. The first wager may be singulated and the second wafer may be singulated to form semiconductor dice.

FIELD

This disclosure relates generally to wafer-level methods of processing,handling, and packaging semiconductor devices. More specifically,disclosed embodiments relate to wafer-level methods of processing,handling, and packaging multiple semiconductor devices that may reducecost, increase yield, and speed throughput.

BACKGROUND

It is a general trend in the electronics industry to decrease the sizeof components while increasing the bandwidth of those components. Forexample, chip-on-wafer techniques may generally eliminate relativelytall or thick electrically conductive elements, such as solder bumps,between the bond pads of individual semiconductor dice and a wafer infavor of smaller electrically conductive elements such as copper pillarsand terminal pads, facilitated by thermocompression bonding.

BRIEF DESCRIPTION OF THE DRAWINGS

While this disclosure concludes with claims particularly pointing outand distinctly claiming specific embodiments, various features andadvantages of embodiments within the scope of this disclosure may bemore readily ascertained from the following description when read inconjunction with the accompanying drawings, in which:

FIG. 1 is a perspective top view of a wafer;

FIG. 2 is a cross-sectional side view of a portion of the wafer of FIG.1 during a first stage in a process of fabricating semiconductor devicepackages;

FIG. 3 is a cross-sectional side view of the portion of the wafer ofFIG. 2 during a second stage in the process of fabricating semiconductordevice packages;

FIG. 4 is a cross-sectional side view of the portion of the wafer ofFIG. 3 during a third stage in the process of fabricating semiconductordevice packages;

FIG. 5 is a cross-sectional side view of the portion of the wafer ofFIG. 4 during a fourth stage in the process of fabricating semiconductordevice packages;

FIG. 6 is a cross-sectional side view of the portion of the wafer ofFIG. 5 during a fifth stage in the process of fabricating semiconductordevice packages; and

FIG. 7 is a cross-sectional side view of a semiconductor device packagefabricated in accordance with this disclosure.

DETAILED DESCRIPTION

The illustrations presented in this disclosure are not meant to beactual views of any particular act in a method of processing, handling,or packaging semiconductor device, semiconductor device itself,semiconductor package, or component thereof, but are merely idealizedrepresentations employed to describe illustrative embodiments. Thus, thedrawings are not necessarily to scale.

Disclosed embodiments relate generally to wafer-level methods ofprocessing, handling, and packaging semiconductor devices that mayreduce cost, increase yield, and speed throughput. More specifically,disclosed are embodiments of processing, handling, and packagingsemiconductor devices at the wafer level that may involve the sequentialformation of trenches in an overlying wafer, placement of dielectricmaterial between the overlying wafer and an underlying wafer,application of force and heat to electrically connect respective regionsof integrated circuitry of adjacent wafers and cause the dielectricmaterial to flow into the trenches, and ultimate separation of theconnected regions from other connected regions to form semiconductordevice packages. By adapting chip-on-wafer techniques, such asthermocompression bonding, to wafer-level handling and assemblytechniques, such as the adaptations summarized above, and described ingreater detail and supplemented below, wafer-to-wafer assembly mayreduce, or eliminate, the need for costly, potentially damaging, andtime-consuming chip-level techniques, such as, for example,pick-and-place application of individual semiconductor dice over anentire wafer.

As used in this disclosure, relative terms based on orientationsdepicted in the figures, such as “upper,” “lower,” “top,” “bottom,”“over,” and “under,” refer to the orientation depicted in the associatedfigures, and are not meant to limit the orientation of the device duringfabrication or use. For example, an upper surface refers to the uppersurface depicted in the associated drawing, but the same surface mayultimately be oriented sideways, downward, or at an angle duringfabrication or use of the device.

As used herein, the terms “substantially” and “about” in reference to agiven parameter, property, or condition means and includes to a degreethat one of ordinary skill in the art would understand that the givenparameter, property, or condition is met with a degree of variance, suchas within acceptable manufacturing tolerances. For example, a parameterthat is substantially or about a specified value may be at least about90% the specified value, at least about 95% the specified value, atleast about 99% the specified value, or even at least about 99.9% thespecified value.

As used herein, the terms “conductive element” and “electricallyconductive element” mean and include a metal or metal alloy material,for example a solder, susceptible to heat-induced reflow at atemperature between, for example, about 90° C. and about 450° C. Themetal or metal alloy material of the conductive element may be in asolid state, or as a mass of metal particles in a binder in the form ofa paste. The conductive element may be carried on another conductivestructure, such as a bond pad, or on a pillar or stud of a highermelting point metal material.

FIG. 1 is a perspective top view of a first wafer 100. The first wafer100 may comprise a semiconductor material (e.g., silicon) to be furtherprocessed into a plurality of semiconductor devices (i.e., semiconductordice). The first wafer 100 may be of any shape, such as, for example, atleast substantially disc-shaped or at least substantially a rectangularprism. The first wafer 100 may include discrete first regions 102 ofintegrated circuitry embedded within, and distributed over, the firstactive surface 104 of the first wafer 100, each discrete first region102 of integrated circuitry being laterally separated from other firstregions 102 by first streets 106. A first backside surface 108 of thefirst wafer 100, which may lack integrated circuitry embedded therein,may be located on a side of the first wafer 100 opposite the activefirst surface 104. First wafer 100 may be cut (i.e., singulated) to formindividual semiconductor device packages. In some embodiments, the firstwafer 100 may comprise only semiconductor material (e.g., silicon) andbe configured conventionally as a disc with a flat or notch on one sidefor alignment purposes.

FIG. 2 is a cross-sectional side view of a portion of the first wafer100 of FIG. 1 during a first stage in a process of fabricatingsemiconductor device packages. The first wafer 100 may be the firstwafer 100 processed in accordance with the methods of this disclosure,and may be configured to form a top-most first wafer 100 duringprocessing, and the top-most die in a stack of dice of semiconductordevice packages formed in accordance with this disclosure. Firstelectrically conductive elements 110 may be positioned on, and extendoutward from, the first active surface 104, and may be located on eachof the first regions 102 of integrated circuitry (e.g., in a repeating,geometric pattern distributed over the first active surface 104) toprovide operative, electrical connection to the integrated circuitry inthe respective first regions 102. First electrically conductive elements110 may be configured, as shown as copper pillars topped with a soldercap and a nickel barrier material between the copper and the solder. Inanother embodiment, first electrically conductive elements 110 may beconfigured only as copper pillars. The first wafer 100 may have a firstthickness T₁, which may represent a maximum, unthinned state of thefirst wafer 100, for example about 650 μm to about 750 μm.

First trenches 112 may be formed in the first streets 106 locatedbetween the first regions 102 of integrated circuitry in the firstactive surface 104 of the first wafer 100. Although the cross-sectionalview of FIG. 2 is only able to show the first trenches 112 runningparallel to one another along certain first streets 106, the firsttrenches 112 may extend along the first streets 106 in each direction,forming a grid of the first trenches 112 around at least some of thefirst regions 102 of integrated circuitry, up to surrounding each of thefirst regions 102 and running along each of the first streets 106.Though the cross-sectional shape of the first trenches 112 depicted inFIG. 2 is at least substantially rectangular, any cross-sectional shapemay be used, though having at least a portion of the first trenches 112beginning at the first active surface 104 and extending toward the firstbackside surface 108 include at least substantially straight sidewallsoriented at least substantially perpendicular to the first activesurface 104 may be desirable. For example, the cross-sectional shape ofthe first trenches 112, as viewed in a plane perpendicular to an edgebetween a sidewall of the first trenches 112 and the first activesurface 104, may be at least substantially rectangular with roundedcorners, a half-round bottom, etc.

The first trenches 112 may extend only partially through the firstthickness T₁ of the first wafer 100, and may be of a first width W₁sufficiently small that the integrated circuitry in the first regions102 located laterally adjacent to the first trenches 112 has a lowlikelihood of being damaged due to the formation of the first trenches112. For example, the first trenches 112 may extend in a directionperpendicular to the first active surface 104, from the first activesurface 104 to between about 20% and about 80% of the first thickness T₁of the first wafer 100. More specifically, the first trenches 112 mayextend from the first active surface 104 to between about 30% and about70% of the first thickness T₁ of the first wafer 100. As a specific,nonlimiting example, the first trenches 112 may extend from the firstactive surface 104 to between about 40% and about 60% (e.g., about 50%,55%, or 60%) of the first thickness T₁ of the first wafer 100. A depth Dof the first trenches 112, as measured in a direction perpendicular tothe first active surface 104, may be, for example, between about 100 μmand about 500 μm. More specifically, the depth D of the first trenches112 may be between about 200 μm and about 400 μm. As a specific,nonlimiting example, the depth D of the first trenches 112 may bebetween about 250 μm and about 350 μm (e.g., about 300 μm). The firstwidth W₁ of the first trenches 112 may occupy, for example, betweenabout 20% and about 80% of the shortest lateral extents of the firststreets 106 between the first regions 102 of integrated circuitry of thefirst wafer 100. More specifically, the first width W₁ of the firsttrenches 112 may occupy, for example, between about 30% and about 70% ofthe lateral extents of the first streets 106. As a specific, nonlimitingexample, the first width W₁ of the first trenches 112 may occupy betweenabout 40% and about 60% (e.g., about 50%, 55%, or 60%) of the lateralextents of the first streets 106. The first width W₁ of the firsttrenches 112 may be, for example, between about 50 μm and about 150 μm.More specifically, the first width W₁ of the first trenches 112 may be,for example, between about 55 μm and about 100 μm. As a specific,nonlimiting example, the first width W₁ of the first trenches 112 may bebetween about 60 μm and about 80 μm (e.g., about 70 μm or 75 μm).

The first trenches 112 may be formed, for example, by removingsemiconductor material of the first wafer 100 from within the firststreets 106, such as, for example, by cutting or etching (e.g., dry orwet) the semiconductor material of the first wafer 100. As a specific,nonlimiting examples, the first trenches 112 may be formed by partiallycutting through the first thickness T₁ of the first wafer 100 utilizinga first dicing saw 114 having a first saw width SW₁ sized and shaped toproduce the first trenches 112 of the first width W₁, or by performing afirst number of dicing passes utilizing the first dicing saw 114sufficient to produce the first width W₁.

FIG. 3 is a cross-sectional side view of the portion of the first wafer100 of FIG. 2 during a second stage in the process of fabricatingsemiconductor device packages. A first quantity of a dielectric material116 may be placed over the first active surface 104, at least partiallysurrounding the first electrically conductive elements 110 located onthe first active surface 104 with the first quantity of the dielectricmaterial 116. A second thickness T₂ of the dielectric material 116 maybe at least substantially equal to, or slightly greater or less than, amaximum height H of the first electrically conductive elements 110 abovethe first active surface 104. The first trenches 112 may remain at leastsubstantially free of the first quantity of the dielectric material 116,such that the dielectric material 116 may extend over the first trenches112 between the first regions 102 of integrated circuitry in the firstactive surface 104, and the first trenches 112 may remain primarilyoccupied by environmental fluid (e.g., air or an inert gas, such asargon).

The dielectric material 116 may include, for example, a non-conductivepolymer material. More specifically, the dielectric material 116 mayinclude, for example, a nonconductive film (NCF), and may be initiallydeposited in an uncured state, over and around first electricallyconductive elements 110. As another specific, nonlimiting example, thedielectric material 116 may be dispensed in a flowable state, forexample as by spin coating, over the first active surface 104 and aroundat least portions of the first electrically conductive elements 110 forsubsequent curing.

FIG. 4 is a cross-sectional side view of the portion of the wafer ofFIG. 3 during a third stage in the process of fabricating semiconductordevice packages. A second wafer 120 comprising a semiconductor materialmay be brought proximate to, and placed in contact with, the dielectricmaterial 116 on a side of the dielectric material 116 opposite the firstwafer 100. The second wafer 120 may generally be configured in a mannersimilar to the first wafer 100, including having a second active surface126 facing the first active surface 104 of the first wafer 100 and asecond backside surface 130 located on a side of the second wafer 120opposite the second active surface 126 and the first wafer 100. Thesecond active surface 126 may include discrete, second regions 124 ofintegrated circuitry embedded within, and distributed across, the secondactive surface 126. The second regions 124 of integrated circuitry maybe operatively, electrically connected to second vias 122 extending fromat least proximate to the second active surface 126, throughsemiconductor material of the second wafer 120 in a direction at leastsubstantially perpendicular to the second active surface 126, to atleast proximate to the second backside surface 130. The second wafer 120may enable electrical and operative connection to the second regions 124of integrated circuitry, and between the second active surface 126 andthe second backside surface 130 utilizing, for example, bond pads 132connected to the second vias 122 at the second active surface 126 andsecond electrically conductive elements 134 positioned on, and extendingoutward from, the second vias 122 at the second backside surface 130.

The second wafer 120 may be supported on a first carrier 128 located ona side of the second wafer 120 opposite the first wafer 100. Forexample, a temporary bonding material 136 may be located on the secondbackside surface 130, may at least partially surround the secondelectrically conductive elements 134 on the second backside surface 130,and may temporarily secure the second wafer 120 to the first carrier128, which may support and reinforce the second wafer 120 duringprocessing and handling. The second wafer 120 may have a third thicknessT₃ smaller than the first thickness T₁ of the first wafer 100, which mayrepresent a final, thinned state of the second wafer 120, for examplebetween about 40 μm and about 70 μm.

First ends 118 of the first electrically conductive elements 110 locateddistal from the first active surface 104 may be operatively connected tothe second vias 122 at the second active surface 126 of the second wafer120, such as, for example, by aligning the first electrically conductiveelements 110 with the second vias 122 and contacting the firstelectrically conductive elements 110 to the bond pads 132. Force may beapplied to the first wafer 100, the second wafer 120, and the firstcarrier 128 while exposing the first wafer 100, the second wafer 120,and the first carrier 128 to an elevated temperature sufficient toreflow the first electrically conductive elements 110. Reflowing thesolder caps of the first electrically conductive elements 110 may causethe first electrically conductive elements 110 to successfully connectoperatively, electrically, and mechanically to the second vias 122(e.g., by way of the bond pads 132). It should be noted that a similartechniques may be employed to diffusion bond copper pillars lackingsolder caps to bond pads. Application of force and exposure to elevatedtemperature may be accomplished by, for example, subjecting the firstwafer 100, the second wafer 120, and the first carrier 128 to athermocompression bonding process. More specifically, application offorce and exposure to elevated temperature may be accomplished byplacing the first wafer 100, the second wafer 120, and the first carrier128 in a container, reducing ambient pressure in the interior of thecontainer to at least a partial vacuum, and placing the container andits contents in a furnace. The applied force may be, for example,between about 2 kN and about 12 kN. More specifically, the applied forcemay be between about 2.5 kN and about 10 kN. As a specific, nonlimitingexample, the applied force may be between about 3 kN and about 8 kN(e.g., about 3.5 kN, about 4 kN, about 4.5 kN, or about 5 kN). Theelevated temperature may be, for example, between about 215° C. andabout 300° C. More specifically, the elevated temperature may be, forexample, between about 225° C. and about 275° C. As a specific,nonlimiting example, the elevated temperature may be between about 240°C. and about 260° C. (e.g., about 245° C., about 250° C., or about 255°C.).

In response to application of force and exposure to elevatedtemperature, portions of the first quantity of the dielectric material116 may flow into the first trenches 112. For example, the firstquantity of the dielectric material 116 may become flowable, if appliedas an NCF, or remain in a flowable state if applied by spin coating, andthe applied force and exposure to elevated temperature may squeeze thefirst wafer 100 and the second wafer 120 toward one another, reducingthe distance and thus the volume, between the first wafer 100 and thesecond wafer 120, and reducing the second thickness T₂ of the firstquantity of the dielectric material 116 between the first wafer 100 andthe second wafer 120. Portions of the dielectric material 116 may flowinto, and at least substantially fill, the first trenches 112 inresponse to the reduction in volume between the first wafer 100 and thesecond wafer 120. For example, voids in the first trenches 112containing environmental fluid (e.g., air or an inert gas, such asargon) may be at least substantially removed, being replaced by thedielectric material 116. After reflowing the solder caps of the firstelectrically conductive elements 110 and causing the dielectric material116 to flow into the first trenches 112, the first electricallyconductive elements 110 and the first quantity of the dielectricmaterial 116, in addition to other components, such as the first wafer100, second wafer 120, and first carrier 128, may be permitted to cool.Cooling may cause the reflowed solder of the first electricallyconductive elements 110 to solidify, forming mechanical and electricalconnections to the second vias 122, and the dielectric material 116 tosolidify, providing electrical isolation between the first wafer 100 andthe second wafer 120, and between the first electrically conductiveelements 110. In some embodiments, application of heat to, andsubsequent cooling of, the dielectric material 116 may cause thedielectric material 116 to cure.

FIG. 5 is a cross-sectional side view of the portion of the first wafer100 of FIG. 4 during a fourth stage in the process of fabricatingsemiconductor device packages. After the second wafer 120 has beenmechanically and electrically connected to the first wafer 100, thefirst carrier 128 (see FIG. 4) may be removed from the second wafer 120.For example, the first carrier 128 (see FIG. 4) may be removed byweakening the temporary bonding material 136 (e.g., by application ofheat, exposure to ultraviolet light, or exposure to a solvent material).The first carrier 128 (see FIG. 4) may then be displaced relative to thesecond wafer 120 (e.g., by sliding in a direction parallel to the secondactive surface 126, or peeling first carrier 128 away from the secondwafer from one side to another).

Second trenches 138 aligned with the first streets 106 may be formed by,for example, removing semiconductor material of the second wafer 120through an entirety of the third thickness T₃ and partially into thedielectric material 116 located between the first wafer 100 and thesecond wafer 120. For example, the first dicing saw 114 may again beused, and the first dicing saw 114 may cut entirely through the secondwafer 120 and partially through the first quantity of the dielectricmaterial 116 in the space between the first wafer 100 and the secondwafer 120. Removing the semiconductor material of the second wafer 120through the entirety of the third thickness T₃ may singulate therespective second regions 124 of integrated circuitry from one another,forming discrete second semiconductor dice 172. The discrete secondsemiconductor dice 172 may still be referred to collectively in thisdisclosure as the second wafer 120 for ease of description. The secondtrenches 138 may have at least substantially the same sizes and shapesdescribed previously in connection with the first trenches 112. In someembodiments, the second trenches 138 may be at least substantially thesame size and shape as the first trenches 112. In other embodiments, thesecond trenches 138 may have a different size, shape, or size and shapefrom the first trenches 112, though still within the location parametersdescribed previously.

FIG. 6 is a cross-sectional side view of the portion of the first wafer100 of FIG. 5 during a fifth stage in the process of fabricatingsemiconductor device packages. A second quantity of the dielectricmaterial 116 may be placed in contact with the second backside surface130 of the second wafer 120, at least partially surrounding the secondelectrically conductive elements 134 located on the second backsidesurface 130 with the dielectric material 116. The second quantity of thedielectric material 116 may be in the form of a material describedpreviously in connection with the first quantity of the dielectricmaterial 116, and may be placed in position by any of the techniquesdescribed previously in connection with the first quantity of thedielectric material 116. In some embodiments, the dielectric material116 of the first and second quantities may be the same material. Inother embodiments the dielectric material 116 of the first quantity maybe different from the dielectric material 116 of the second quantity.

A third wafer 140 comprising a semiconductor material may be broughtproximate to, and placed in contact with, the second quantity of thedielectric material 116 on a side of the dielectric material 116opposite the second wafer 120. The third wafer 140 may generally beconfigured in a manner similar to the first wafer 100, including havinga third active surface 142 facing the second backside surface 130 of thesecond wafer 120 and a third backside surface 144 located on a side ofthe third wafer 140 opposite the third active surface 142, the firstwafer 100, and the second wafer 120. The third active surface 142 mayinclude discrete, third regions 146 of integrated circuitry embeddedwithin, and distributed across, the third active surface 142. The thirdregions 146 of integrated circuitry may be operatively, electricallyconnected to third vias 148 extending from at least proximate to thethird active surface 142, through semiconductor material of the thirdwafer 140 in a direction at least substantially perpendicular to thethird active surface 142, to at least proximate to the third backsidesurface 144. The third wafer 140 may enable electrical and operativeconnection to the third regions 146 of integrated circuitry, and betweenthe third active surface 142 and the third backside surface 144utilizing, for example, bond pads 132 connected to the third vias 148 atthe third active surface 142 and third electrically conductive elements150 positioned on, and extending outward from, the third vias 148 at thethird backside surface 144.

The third wafer 140 may be supported on a second carrier 152 located ona side of the third wafer 140 opposite the second wafer 120. Forexample, a temporary bonding material 136 may be located on the thirdbackside surface 144, may at least partially surround the thirdelectrically conductive elements 150 on the third backside surface 144,and may temporarily secure the third wafer 140 to the second carrier152, which may support and reinforce the third wafer 140 duringprocessing and handling. The third wafer 140 may have the thirdthickness T₃ smaller than the first thickness T₁ of the first wafer 100,which may represent a final, thinned state of the third wafer 140, forexample between about 40 μm and about 70 μm.

Second ends 154 of the second electrically conductive elements 134located distal from the second active surface 126 may be operativelyconnected to the third vias 148 at the third active surface 142 of thethird wafer 140, such as, for example, by aligning the secondelectrically conductive elements 134 with the third vias 148 andcontacting the second electrically conductive elements 134 to the bondpads 132. Force may be applied to the first wafer 100, the second wafer120, the third wafer 140, and the second carrier 152 while exposing thefirst wafer 100, the second wafer 120, the third wafer 140, and thesecond carrier 152 to an elevated temperature sufficient to reflow thesolder caps of the second electrically conductive elements 134.Reflowing the solder caps of the second electrically conductive elements134 may cause the second electrically conductive elements 134 tosuccessfully connect operatively, electrically, and mechanically to thethird vias 148 (e.g., by way of the bond pads 132). Application of forceand exposure to elevated temperature may be accomplished by, forexample, subjecting the first wafer 100, the second wafer 120, the thirdwafer 140, and the second carrier 152 to a thermocompression bondingprocess, as described previously in connection with FIG. 4.

In response to application of force and exposure to elevatedtemperature, portions of the second quantity of the dielectric material116 may flow into the second trenches 138. For example, the secondquantity of the dielectric material 116, depending on the naturethereof, may be caused to become flowable or may remain in a flowablestate, and the applied force and exposure to elevated temperature maysqueeze the second wafer 120 and the third wafer 140 toward one another,reducing the distance and thus the volume between the second wafer 120and the third wafer 140. Portions of the dielectric material 116 mayflow into, and at least substantially fill, the second trenches 138 inresponse to the reduction in space between the second wafer 120 and thethird wafer 140. For example, voids in the second trenches 138containing environmental fluid (e.g., air or an inert gas, such asargon) may be at least substantially removed, being replaced by thedielectric material 116. After reflowing the second electricallyconductive elements 134 and causing the dielectric material 116 to flowinto the second trenches 138, the second electrically conductiveelements 134 and the second quantity of the dielectric material 116, inaddition to other components, such as the first wafer 100, second wafer120, third wafer 140, and second carrier 152, may be permitted to cool.Cooling may cause the solder of the second electrically conductiveelements 134 to solidify, forming mechanical and electrical connectionsto the third vias 148, and the dielectric material 116 to solidify,providing electrical isolation between the second wafer 120 and thethird wafer 140, and between the second electrically conductive elements134. In some embodiments, application of heat to, and subsequent coolingof, the dielectric material 116 may cause the dielectric material 116 tocure.

At least the first wafer 100 and second wafer 120, and optionally thethird wafer 140 and any additional wafers, may collectively form astack, which may be expanded or maintained at just two wafers, dependingon the intended application and configuration for the integratedcircuitry of the various wafers. For example, a number of wafers in thestack may be between two (i.e., just the first wafer 100 and the secondwafer 120) and sixteen. More specifically, the number of wafers in thestack may be between four and eight (e.g., may be exactly four orexactly eight). To form the stack, the acts of FIGS. 5 and 6 may berepeated, including forming additional trenches that singulate amost-recently added wafer in situ, adding dielectric material,contacting another wafer, and reflowing electrically conductive elementsand flowing the dielectric material into the trench, until the totalnumber of wafers in the stack reaches a desired final number.

FIG. 7 is a cross-sectional side view of a semiconductor device package160 produced in accordance with this disclosure. To form thesemiconductor device package 160 shown in FIG. 7, the second carrier 152(see FIG. 6) may be removed from the third wafer 140. Third trenches 166aligned with the first streets 106 may be formed by, for example,removing semiconductor material of the third wafer 140 through anentirety of the third thickness T₃ and partially into the dielectricmaterial 116 located between the second wafer 120 and the third wafer140. A third quantity of the dielectric material 116 may be placed incontact with the third backside surface 144 of the third wafer 140. Afourth wafer 162 comprising a semiconductor material may be broughtproximate to, and placed in contact with, the third quantity of thedielectric material 116 on a side of the dielectric material 116opposite the third wafer 140. The fourth wafer 162 may be supported on athird carrier (not shown) and may have the third thickness T₃ smallerthan the first thickness T₁ of the first wafer 100, which may representa final, thinned state of the third wafer 140, for example between about40 μm and about 70 μm.

Third ends 164 of the third electrically conductive elements 150 locateddistal from the third active surface 142 may be operatively connected tofourth vias 190 at the fourth active surface 188 of the fourth wafer162. Force may be applied to the first wafer 100, the second wafer 120,the third wafer 140, the fourth wafer 162, and the third carrier whileexposing the first wafer 100, the second wafer 120, the third wafer 140,the fourth wafer 162, and the third carrier to an elevated temperaturesufficient to reflow the solder caps of the third electricallyconductive elements 150. In response to application of force andexposure to elevated temperature, portions of the third quantity of thedielectric material 116 may flow into the third trenches 166. Afterreflowing the solder of the third electrically conductive elements 150and causing the dielectric material 116 to flow into the third trenches166, the second electrically conductive elements 134 and the secondquantity of the dielectric material 116, in addition to othercomponents, such as the first wafer 100, second wafer 120, third wafer140, and second carrier 152, may be permitted to cool. No additionaltrenches may be formed through the fourth wafer 162 in embodiments wherethe fourth wafer 162 is the bottom-most, furthest wafer from the firstwafer 100.

The first thickness T₁ of the first wafer 100 may be reduced from a sideof the first wafer 100 opposite the second wafer 120 and revealing theportions of the dielectric material 116 in the first trenches 112. Forexample, semiconductor material of the first wafer 100 may be removedfrom the first backside surface 108 at least until the first thicknessT₁ of the first wafer 100 is equal to the depth D of the first trenches112, and may optionally be continued until the first thickness T₁ of thefirst wafer 100 is less than the depth D of the first trenches 112 afterinitial formation. Reduction of the first thickness T₁ may beaccomplished, for example, by one or more of backgrinding, etching(e.g., dry or wet etching) or chemical mechanical planarization of thefirst wafer 100. Reducing the first thickness T₁ of the first wafer 100in this manner may also singulate the respective first regions 102 ofintegrated circuitry from one another, forming discrete firstsemiconductor dice 170.

The first regions 102 of integrated circuitry may be separated from oneanother, the second regions 124 of integrated circuitry may be separatedfrom one another, the third regions 146 of integrated circuitry may beseparated from one another, and fourth regions 180 of integratedcircuitry of the fourth wafer 162 may be separated from one another toform semiconductor device packages. For example, singulation may beaccomplished by cutting through the portions of the dielectric material116 in the first trenches 112, second trenches 138, and third trenches166 to physically separate the first dice 170, second dice 172, andthird dice 174 from the first wafer 100, second wafer 120, and thirdwafer 140. Singulation may also involve cutting through portions of thefourth wafer 162 aligned with the first streets 106, forming fourth dice176. As specific, nonlimiting examples, singulation may occur by cuttingthrough the dielectric material 116 and the fourth wafer 162 utilizing asecond dicing saw 182 having a second saw width SW₂ less than the firstsaw width SW₁ of the first dicing saw 114 (see FIG. 2), or by performinga second, different number of dicing passes utilizing the first dicingsaw 114 (see FIG. 2) or second dicing saw 182 sufficient to formseparation gaps of a second width smaller than the first width W₁ (seeFIG. 2). As a result, portions of the dielectric material 116 may remainon side surfaces 184 of the first dice 170, second dice 172, and thirddice 174, and the side surfaces 186 of the fourth dice 176 may be freeof the dielectric material 116. In addition, the fourth dice 176 mayextend laterally beyond the lateral peripheries of the first dice 170,second dice 172, and third dice 174 formed by the side surfaces 184. Thethird carrier may be removed from the fourth wafer 162.

As illustrative embodiments within the scope of this disclosure, methodsof fabricating semiconductor device packages may involve formingtrenches in streets between first regions of integrated circuitry in afirst active surface of a first wafer. A dielectric material may beplaced over the first active surface. Ends of electrically conductiveelements protruding from the first active surface may be placedproximate bond pads operatively connected to second regions ofintegrated circuitry at a second active surface of a second wafer withthe dielectric material interposed between the first active surface andthe second active surface. Force may be applied perpendicular to thefirst wafer and the second wafer while exposing the first wafer and thesecond wafer to an elevated temperature sufficient to cause theelectrically conductive elements to contact the bond pads. Portions ofthe dielectric material may flow into the trenches during application ofthe force. The elevated temperature may be reduced to connect theelectrically conductive elements to the bond pads and at least partiallysolidify the dielectric material. A thickness of the first wafer may bereduced from a side of the first wafer opposite the second wafer toreveal the portions of the dielectric material in the trenches. Thefirst regions of integrated circuitry may be separated from one anotherand the second regions of integrated circuitry may be separated from oneanother to form singulated semiconductor dice by removing portions ofthe dielectric material in the trenches and leaving portions of thedielectric material covering sidewalls of the singulated semiconductordice.

As additional, illustrative embodiments within the scope of thisdisclosure, methods of fabricating semiconductor device packages mayinvolve forming trenches in streets between first regions of integratedcircuitry of a first active surface of a first semiconductor wafer bycutting partially through the first semiconductor wafer. Dielectricmaterial may be placed in contact with the first active surface at leastpartially surrounding first electrically conductive elements located onthe first active surface. Ends of the first electrically conductiveelements to bond pads connected to second regions of integratedcircuitry at a second active surface of a second semiconductor waferwith the dielectric material between the first semiconductor wafer andthe second semiconductor wafer while the second semiconductor is wafersupported on a first carrier located on a side of the second waferopposite the first wafer. Force may be applied to the first wafer, thesecond wafer, and the first carrier while exposing the first wafer, thesecond wafer, and the first carrier to an elevated temperaturesufficient to reflow portions of the first electrically conductiveelements. Portions of the first quantity of the dielectric material mayflow into the first trenches. The first electrically conductive elementsand the dielectric material may between the first semiconductor waferand the second semiconductor wafer may be permitted to cool. The secondcarrier may be removed. Second trenches aligned with the streets may beformed by cutting entirely through the second wafer and partially intothe dielectric material. Dielectric material may be placed in contactwith a second backside surface of the second wafer located on a side ofthe second wafer opposite the second active surface, at least partiallysurrounding second electrically conductive elements located on thesecond backside surface and electrically connected to vias of the secondsemiconductor wafer with the dielectric material. Ends of the secondelectrically conductive elements may be operatively connected to viasconnected to third regions of integrated circuitry of a third activesurface of a third semiconductor wafer with dielectric materialinterposed between the second semiconductor wafer and the thirdsemiconductor wafer while the third wafer is supported on a secondcarrier located on a side of the third wafer opposite the second wafer.Force may be applied to the first wafer, the second wafer, the thirdwafer, and the second carrier while exposing the first wafer, the secondwafer, the third wafer, and the second carrier to an elevatedtemperature sufficient to reflow portions of the second electricallyconductive elements. Portions of the dielectric material may flow intothe second trenches. The second electrically conductive elements and thesecond quantity of the dielectric material located between the secondsemiconductor wafer and the third semiconductor wafer may be permittedto cool. A thickness of the first semiconductor wafer may be reducedfrom a side of the first semiconductor wafer opposite the secondsemiconductor wafer and revealing the portions of the dielectricmaterial in the trenches. The second carrier may be removed. The firstregions of integrated circuitry may be separated from one another andthe second regions of integrated circuitry may be separated from oneanother at least partially by cutting through portions of the dielectricmaterial in the trenches.

As shown in FIG. 7, semiconductor device packages 160 produced inaccordance with this disclosure may include a first, top-most die 170having a first backside surface 108 lacking integrated circuitry thereinexposed at an exterior of the semiconductor device packages 160. A firstactive surface 104 located on a side of the first die 170 opposite thefirst backside surface 108 and having integrated circuitry therein maybe covered with a dielectric material 116, which may extend contiguouslyfrom under the first active surface 104 to cover side surfaces 184 ofthe first die 170 extending between the first active surface 104 and thefirst backside surface 108. The dielectric material 116 may be at leastsubstantially flush with the first backside surface 108 at the exteriorof the semiconductor device package 160.

At least a second, intermediate die 172 may be located proximate to thefirst active surface 104 of the first die 170 such that the dielectricmaterial 116 is interposed between the first die 170 and the second die172. First electrically conductive elements 110 may extend from thefirst active surface 104 of the first die 170 to a second active surface126 of the second die 172 having integrated circuitry therein and facingthe first active surface 104 of the first die 170. The firstelectrically conductive elements 110 may be operatively connected tosecond vias 122 extending between the second active surface 126 and asecond backside surface 130 of the second die 172 located on a side ofthe second die 172 opposite the first die 170. The second backsidesurface 130 may be covered with the dielectric material 116, which mayextend contiguously from under the second backside surface 130 to coverside surfaces 184 of the second die 172 extending between the secondactive surface 126 and the second backside surface 130. As shown in FIG.7, additional intermediate dice, such as the third die 174, may belocated on a side of the second die 172 opposite the first die 170, andelectrically conductive elements of an immediately overlying die, suchas the second electrically conductive elements 134 of the second die172, may be operatively connected to complementary vias of theunderlying intermediate die, such as the third vias 148 of the third die174. The backside surfaces of the intermediate dice, such as the thirdbackside surface 144 of the third die 174, may be covered by thedielectric material 116, which may extend contiguously from under therespective backside surface to cover side surfaces 184 of the respectivedie.

A bottom-most die, which in FIG. 7 is the fourth die 176, may be locatedproximate to the backside surface of the immediately overlying die, suchas the third backside surface 144 of the third die 174, such that thedielectric material 116 is interposed between the immediately overlyingdie and the bottom-most die. Overlying electrically conductive elementsmay extend from the backside surface of the overlying die to abottom-most active surface of the bottom-most die, such as the fourthactive surface 188 of the fourth die 176. The overlying electricallyconductive elements may be operatively connected to bottom-most viasextending between the bottom-most active surface and a bottom-mostbackside surface of the bottom-most die, such as the fourth vias 190extending between the fourth active surface 188 and a fourth backsidesurface 192. The bottom-most backside surface may be exposed, andbottom-most electrically conductive elements operatively connected tothe bottom-most or fourth vias 190 may extend from the bottom-mostbackside surface for electrical, mechanical, and operative connection toanother device or structure, such as the fourth electrically conductiveelements 194 located on the fourth backside surface 192. The bottom-mostor fourth die 176 may extend laterally beyond the lateral peripheries ofthe overlying dice in the stack, such that the side surfaces 186 of thebottom-most or fourth die 176 may be exposed at the exterior of thesemiconductor device package 160. The dielectric material 116 coveringthe side surfaces 184 of the overlying dice may cover the lateralperiphery of the bottom-most active surface, in FIG. 7 covering thelateral periphery of the fourth active surface 188 of the fourth die 176extending beyond the lateral peripheries of semiconductor dice 170, 172and 174.

While the semiconductor device package 160 of the present disclosure hasbeen described in terms of the second and third semiconductor dice 172and 174 between first semiconductor die 170 and semiconductor die 176 ashaving active surfaces facing first semiconductor die 170, second andthird semiconductor dice 172 and 174 may be oriented with activesurfaces facing away from first die 170. Similarly semiconductor die 176may be oriented with an active surface facing away from firstsemiconductor die 170, so that the active surfaces of all dice in thepackage are similarly oriented. Of course, suitable passivation materialwould be applied to the exposed active surface to protect the integratedcircuitry thereon, as is known in the art.

In some embodiments, the semiconductor device package 160 may beconfigured as a memory module. For example, the bottom-mostsemiconductor die, or the fourth die 176 in FIG. 7, may be configured asa logic die for controlling operating of the memory module andcommunicating with other operatively connected devices, and theoverlying dice, or the first die 170, second die 172, and third die 174in FIG. 7, may be configured as memory dice for storing data.Semiconductor device packages 160 fabricated at the wafer level may befabricated in a less costly, more rapid manner than conventional,multi-die packages such as so-called hybrid memory cubes, and withhigher yields.

As illustrative embodiments in accordance with this disclosure,semiconductor device packages may include a bottom-most semiconductordie comprising external electrically conductive elements located on abackside surface thereof, the external electrically conductive elementselectrically connected to vias extending from the backside surface to anactive surface comprising integrated circuitry and located on a side ofthe bottom-most semiconductor die opposite the backside surface. Atleast one intermediate semiconductor die stacked over the bottom-mostsemiconductor die, each intermediate semiconductor die comprisingelectrically conductive elements located on a backside surface of therespective at least one intermediate semiconductor die, the electricallyconductive elements electrically connected to vias extending from thebackside surface to an active surface comprising integrated circuitryand located on a side of the respective intermediate semiconductor dieopposite the backside surface thereof and to the bond pads of anunderlying intermediate die or the bottom-most die. A top-mostsemiconductor die located on a side of a farthest intermediatesemiconductor die from the bottom-most semiconductor die opposite thebottom-most semiconductor die, the top-most semiconductor die comprisinga semiconductor material and electrically conductive elements located onan active surface of the top-most die comprising integrated circuitry,the electrically conductive elements of the top-most semiconductor dieelectrically connected to bond pads of the farthest intermediatesemiconductor die from the bottom-most semiconductor die, the activesurface of the top-most semiconductor die facing toward the bottom-mostsemiconductor die, wherein the bottom-most semiconductor die extendsbeyond lateral peripheries of each intermediate semiconductor die andthe top-most semiconductor die. A dielectric material may be locatedbetween each of the semiconductor dice, at least sections of thedielectric material extending contiguously from between adjacentsemiconductor dice, laterally beyond the lateral peripheries all but thebottom-most semiconductor die and over sidewalls thereof.

While certain illustrative embodiments have been described in connectionwith the figures, those of ordinary skill in the art will recognize andappreciate that the scope of this disclosure is not limited to thoseembodiments explicitly shown and described in this disclosure. Rather,many additions, deletions, and modifications to the embodimentsdescribed in this disclosure may be made to produce embodiments withinthe scope of this disclosure, such as those specifically claimed,including legal equivalents. In addition, features from one disclosedembodiment may be combined with features of another disclosed embodimentwhile still being within the scope of this disclosure, as contemplatedby the inventor.

What is claimed is:
 1. A method of fabricating a semiconductor devicepackage, comprising: forming trenches in streets between first regionsof integrated circuitry in a first active surface of a first wafer;placing a dielectric material over the first active surface; placingends of electrically conductive elements protruding from the firstactive surface proximate bond pads operatively connected to secondregions of integrated circuitry at a second active surface of a secondwafer with the dielectric material interposed between the first activesurface and the second active surface; applying force perpendicular tothe first wafer and the second wafer while exposing the first wafer andthe second wafer to an elevated temperature sufficient to cause theelectrically conductive elements to contact the bond pads; flowingportions of the dielectric material into the trenches during applicationof the force; reducing the elevated temperature to at least partiallysolidify the dielectric material; reducing a thickness of the firstwafer from a side of the first wafer opposite the second wafer to revealthe portions of the dielectric material in the trenches; and separatingthe first regions of integrated circuitry from one another and thesecond regions of integrated circuitry from one another to formsingulated semiconductor dice by removing a first part of the portionsof the dielectric material in the trenches and leaving a second part ofthe portions of the dielectric material covering sidewalls of thesingulated semiconductor dice.
 2. The method of claim 1, furthercomprising supporting the second wafer on a carrier before connectingthe ends of the electrically conductive elements to the bond pads of thesecond wafer.
 3. The method of claim 2, wherein supporting the secondwafer on the carrier comprises contacting a second backside surface ofthe second wafer located on a side of the second wafer opposite thesecond active surface to the carrier with a temporary bonding materialand at least partially surrounding second electrically conductiveelements located on the second backside surface and electricallyconnected to vias of the second wafer with the temporary bondingmaterial and further comprising removing the carrier after theelectrically conductive elements are connected to the bond pads and thedielectric material is in a substantially solid state.
 4. The method ofclaim 1, further comprising, before reducing the thickness of the firstwafer, forming other trenches aligned with the streets, the othertrenches extending through the second wafer and into the dielectricmaterial located between the first wafer and the second wafer.
 5. Themethod of claim 4, further comprising, before reducing the thickness ofthe first wafer: placing a second quantity of the dielectric materialover a second backside surface of the second wafer located on a side ofthe second wafer opposite the second active surface, at least partiallysurrounding second electrically conductive elements located on thesecond backside surface and electrically connected to vias of the secondwafer with the second quantity of the dielectric material; operativelyconnecting ends of the second electrically conductive elements distalfrom the second backside surface to bond pads operatively connected tothird regions of integrated circuitry at a third active surface of athird wafer, the second quantity of the dielectric material interposedbetween the second backside surface and the third active surface;applying force perpendicular to the first wafer, the second wafer, andthe third wafer while exposing the first wafer, the second wafer, andthe third wafer to the elevated temperature to cause the secondelectrically conductive elements to contact the bond pads of the thirdwafer; flowing portions of the second quantity of the dielectricmaterial into the other trenches during the application of perpendicularforce; and reducing the elevated temperature to at least partiallysolidify the second quantity of the dielectric material.
 6. The methodof claim 5, further comprising supporting the third wafer on a carrierbefore connecting the ends of the second electrically conductiveelements to vias of the third wafer.
 7. The method of claim 6, whereinsupporting the third wafer on the carrier comprises contacting a thirdbackside surface of the third wafer located on a side of the third waferopposite the third active surface to the carrier with a temporarybonding material and at least partially surrounding third electricallyconductive elements located on the third backside surface andelectrically connected to the vias of the third wafer with the temporarybonding material and further comprising removing the carrier after thesecond electrically conductive elements are connected and the secondquantity of the dielectric material is in a substantially solid state.8. The method of claim 1, wherein placing the dielectric material overthe first active surface comprises placing a nonconductive film over thefirst active surface.
 9. The method of claim 1, wherein applying theperpendicular force to the first wafer and the second wafer whileexposing the first wafer and the second wafer to the elevatedtemperature sufficient to reflow the electrically conductive elementscomprises subjecting the first wafer and the second wafer to athermocompression bonding process.
 10. The method of claim 1, whereinforming the trenches in the streets of the first wafer comprisesutilizing a saw to cut partially through the first wafer.
 11. The methodof claim 1, wherein forming the trenches in the streets between thefirst regions of integrated circuitry of the first wafer comprisesforming the trenches in the streets between the first regions ofintegrated circuitry, the first regions of integrated circuitrycomprising memory devices, of the first wafer and wherein separating thefirst regions of integrated circuitry from one another and the secondregions of integrated circuitry from one another comprises separatingthe first regions of integrated circuitry from one another and thesecond regions of integrated circuitry from one another in such a waythat farthest regions of integrated circuitry from the first regions ofintegrated circuitry comprise logic devices and any intervening regionsof integrated circuitry between the first regions of integratedcircuitry and the farthest regions of integrated circuitry comprisememory devices.
 12. The method of claim 1, wherein applying theperpendicular force to the first wafer and the second wafer furthercomprises applying at least a partial vacuum to an interior of acontainer in which the first wafer and the second wafer are located. 13.The method of claim 1, wherein applying perpendicular force to the firstwafer and the second wafer comprises applying between 2 kN and 12 kN offorce to the first wafer and the second wafer.
 14. The method of claim1, wherein exposing the first wafer and the second wafer to the elevatedtemperature comprises exposing the first wafer and the second wafer to atemperature of between about 215° C. and about 300° C.
 15. A method offabricating a semiconductor device package, comprising: forming firsttrenches in streets between first regions of integrated circuitry of afirst active surface of a first semiconductor wafer by cutting partiallythrough the first semiconductor wafer; placing a first quantity of adielectric material in contact with the first active surface at leastpartially surrounding first electrically conductive elements located onthe first active surface; operatively connecting ends of the firstelectrically conductive elements to bond pads connected to secondregions of integrated circuitry at a second active surface of a secondsemiconductor wafer with the first quantity of the dielectric materialbetween the first semiconductor wafer and the second semiconductor waferwhile the second semiconductor is wafer supported on a first carrierlocated on a side of the second semiconductor wafer opposite the firstsemiconductor wafer; applying force to the first semiconductor wafer,the second semiconductor wafer, and the first carrier and reflowingportions of the first electrically conductive elements; flowing portionsof the first quantity of the dielectric material into the firsttrenches; permitting the first electrically conductive elements and thefirst quantity of the dielectric material to cool; removing the firstcarrier; forming second trenches aligned with the streets by cuttingentirely through the second semiconductor wafer and partially into thefirst quantity of the dielectric material; placing a second quantity ofthe dielectric material in contact with a second backside surface of thesecond semiconductor wafer located on a side of the second semiconductorwafer opposite the second active surface, at least partially surroundingsecond electrically conductive elements located on the second backsidesurface and electrically connected to vias of the second semiconductorwafer with the second quantity of the dielectric material; operativelyconnecting ends of the second electrically conductive elements to viasconnected to third regions of integrated circuitry of a third activesurface of a third semiconductor wafer with the second quantity of thedielectric material interposed between the second semiconductor waferand the third semiconductor wafer while the third semiconductor wafer issupported on a second carrier located on a side of the thirdsemiconductor wafer opposite the second semiconductor wafer; applyingforce to the first semiconductor wafer, the second semiconductor wafer,the third semiconductor wafer, and the second carrier and reflowingportions of the second electrically conductive elements; flowingportions of the second quantity of the dielectric material into thesecond trenches; permitting the second electrically conductive elementsand the second quantity of the dielectric material to cool; reducing athickness of the first semiconductor wafer from a side of the firstsemiconductor wafer opposite the second semiconductor wafer andrevealing the portions of the first quantity of the dielectric materialin the first trenches; removing the second carrier; and separating thefirst regions of integrated circuitry from one another, the secondregions of integrated circuitry from one another, and the third regionsof integrated circuitry from one another at least partially by cuttingthrough portions of the first and second quantities of the dielectricmaterial in the trenches.
 16. The method of claim 15, further comprisingseparating the third regions of integrated circuitry from one another bycutting through an entire thickness of the third semiconductor wafer.17. The method of claim 15, wherein forming the first trenches in thestreets of the first semiconductor wafer and forming the second trenchesaligned with the streets by cutting entirely through the secondsemiconductor wafer and partially into the first quantity of thedielectric material comprises utilizing a saw.
 18. The method of claim17, wherein separating the first regions of integrated circuitry fromone another, the second regions of integrated circuitry from oneanother, and the third regions of integrated circuitry from one anothercomprises cutting through the portions of the first quantity and thesecond quantity of the dielectric material in the trenches and afarthest semiconductor wafer from the first semiconductor waferutilizing another saw having a blade width less than a width of the sawused to form the first trenches and the second trenches.
 19. The methodof claim 15, wherein reducing the thickness of the first semiconductorwafer comprises at least one of back-grinding the first semiconductorwafer, etching the first semiconductor wafer and chemical mechanicalpolishing the first semiconductor wafer.